Watershed Management

The Watershed Management research was started in the Pakistan Forest Institute with the creation of a branch in 1966. The facility was strengthened during the period from 1982 to 1991 through a development project and assistance of FAO/UNDP. It is responsible for conducting applied research in soil and water conservation, water harvesting and slope stabilization. It consists of one Watershed Management Specialist, two Assistant Silviculturist, one Research Officer and four Field Assistants. It also imparts training in Watershed Management, Soil Conservation to B.Sc. and M.Sc. Forestry students.

Significant achievements:

Studies have been conducted in the past on soil and water conservation, water harvesting and critical slope stabilization. Six watershed research stations have been established in different ecological zones of the country for conducting long-term watershed management research because sufficient time is needed for obtaining useful results. Most of the studies in this discipline have been started few years back. Therefore, only results are available. A brief account of significant achievement in research is given below:

Watershed research in scrub zone at Missa Keswal (Punjab): Data on hydrometerology of treated and untreated watersheds, covering a period of sixteen years, have showed that planting of trees, protection from grazing and installation of gully erosion control structures reduce the sediment yield and surface runoff by 63% and 48% respectively in scrub zone with loess soil.

Watershed research in sub-tropical chir pine zone at Fazagut, Swat:Different vegetation treatments were tested for finding the suitable tree species or combination of tree species for the rehabilitation of denuded watersheds. The results indicate that a mixed planting of chir pine and broad leave tree species with channel erosion control measures is effective treatment for denuded catchments.

Watershed research in moist temperate zone at Chakar (AJK):The results show that hydrological response is highest from terraced agriculture land and lowest from the catchment covered with blue pine forest, while the sediment loss is highest in degraded rangelands, followed by agriculture lands and was lowest in the forested land. The results show that forest is best land use for regulating the stream flow as well as erosion control in this ecological zone.

Ground water recharge research in Quetta valley: Ground water recharge works were carried out in Quetta valley. The treatments included contour trenches, check dams, percolation ditches and detention dams. The results of the research studies show that watershed treatments were effective in reducing the surface runoff and enhancing the infiltration in the catchments. It was also observed that main recharge zone are stream beds.

Watershed reseach in dry zone area, Loralai, Balochistan: A research station was established in Loralai district in order to develop technology for proper management of arid watersheds. The studies proved the efficacy of afforestation, water conservation and range improvement techniques and natural vegetation with and without protection, on water and sediment yield.

Soil conservation study at Chattar Kalas (AJK): The results show that bio-technical control measures reduce the erosion rate to one sixth and only technical control measures (contour bunds/check dams) reduce the sediment yield to one third of that of untreated areas.

Investigation of the effect of soil conservation measures on agriculture/tree crop production and sediment yield at Kharian: A study has been carried out to investigate the effect of terracing, conservation benches and strip cropping on erosion control and on agriculture/tree crop production in the scrub zone. The results show that terracing with planting of iple iple tree on risers was quite effective in controlling runoff and sediment yield as compared to conservation benches and strip cropping.

Mountain slope development by planting of forage tree and grass species and by soil conservation techniques in Kund Forest: The resuslts of the study show that planting of improved varieties of legumes and grasses on terraces, hillside ditches and staggered troughs not only increases the forage production but is also effective in reducing the erosion rate in moist temperate zone.

Water conservation techniques: Water conservation techniques have been developed and tested in different localities for the establishment of plantations of forest tree species. Microcatchments, conservation trenches, hillside ditches were found effective not only in increasing the survival rate but also in almost doubling the growth rate of fast growing tree species such as Eucalyptus camaldulensis, Acacia nilotica and Leuceana leucocephala in the scrub zone at Kharian, Kohat and Loralai. In Quetta valley the techniques were found effective reducing surface runoff as well as sediment yield by 100 percent.

Water harvesting studies: Rain water harvesting experiments were conducted at Kharian (Punjab), D.I. Khan (NWFP) and Dagarkotli (Punjab). Roaded catchments with 2-4 meter slope length and 7% gradient were found effective in enhancing the surface runoff for water resource development. In addition to increasing agriculture crops production, forest tree species such as Eucalyptus camaldulensis, Acacia nilotica and Acacia albida were successfully planted with the system.

Critical slope stabilization: Through the experiments conducted on bioengineering techniques for critical slope stabilization it was found that techniques such as brush layering, brush hedge layering, brush wattles and saccharum hedges were successful in stabilizing the critical slopes. Saccharum hedges treatment was found economical in the scrub zone.

Land slide control: Two critical land slides one in Murree area and other in Azad Jammu and Kashmir were stabilized success-fully by adopting scientific control measures. A study on the consumptive use of water by different tree species used for planting the slide areas has been started at Bhurban, Muree.

Plot studies: Plot studies conducted at Ghoragali showed that sediment yield from the plots under pole crop of chir pine, young chir pine, fair grass cover, depleted grass and bare soil was 0.47, 1.81, 4.24, 20.39 and 72 tonns/ha/year respectively. The same trend was also found for the hydrological response. At Balakot the old chir pine crop, natural vegetation with and without grazing yield 0.07, 0.1 and 0.23 tonns of sediment/ha/ year while at Batagram the sediment yield from the plots with Robinia planting with natural vegetation, chir pine with natural vegetation, natural vegetation without grazing and natural vegetation with grazing was 0.16, 0.18, 0.23 and 0.39 tonns/ha/year respectively. A new study is being established at Kharian with 30 x 10 meter plots to investigate the effect of different land uses and vegetation on water and sediment yield.